Abstract

Introduction: Evidence suggests that extraspinal general skeletal overgrowth in AIS girls is associated with the relative anterior spinal overgrowth (RASO) giving such overgrowth pathogenetic significance.
Objectives: To compare skeletal sizes for age of preoperative AIS/normal girls by higher and lower BMI subsets relative to median values in a cross-sectional study.
Materials and Methods: Preoperative (n=122) and normal girls (n=274) age 11–18 years were measured using the Holtain equipment. BMI was weight in kg/stature in meters2 corrected for scoliosis. Skeletal sizes for each of stature, sitting height, subischial height, trunk widths (biacromial and biiliac) and limb segment lengths bilaterally (upper arm, forearm-with-hand, tibia, and foot) were compared within each BMI subset (ANOVA correcting for age). Spinal deformity was measured. Menarcheal age was recorded.
Results: With relatively higher BMIs, preoperative girls from 11 years have larger skeletal segments than normals, decreasing to normal size by 16 years, in each of 11 skeletal segments, six in paired limb bones but not feet. BMIs and menarcheal ages are similar. With relatively lower BMIs, two growth phases are evident: early with skeletal sizes of preoperatives mostly similar to normals; and late, larger than normals. Menarche in preoperatives is later than normals but not statistically significant.
Conclusion: Overall, preoperative girls show skeletal overgrowth patterns which are systemic, probably hormonally driven, for the relatively higher BMI subset somatotropic (growth hormone/IGF) axis, and the relatively lower BMI subset, estrogen.
Significance: Circulating hormones in AIS girls by relatively higher and lower BMI need study, leading to possible medical therapy.